Aligator Rock Swell Statistics, Winter: Surf with Light or Offshore Winds
This image shows only the swells directed at Aligator Rock that coincided with light winds or offshore conditions through a typical northern hemisphere winter. It is based on 6931 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. Green and yellow show increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the dominant swell direction, shown by the largest spokes, was NW, whereas the the dominant wind blows from the E. The chart at the bottom shows the same thing but without direction information. For example, swells larger than 1.5 feet (0.5m) coincided with good wind conditions 55% of the time, equivalent to 50 days. Expect open water swells to exceed >3m (>10ft) 16% of the time (15 days). Taking into account the proportion of these swells that coincided with predicted offshore winds, and given the fact that Aligator Rock is exposed to open water swells, we estimate that clean surf can be found at Aligator Rock about 55% of the time and that surf is spoilt by onshore wind 21% of the time. This is means that we expect 69 days with waves in a typical northern hemisphere winter, of which 50 days should be clean enough to surf.
IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.